Carbon black furnace apparatus

ABSTRACT

The flow rate of quench fluid in a furnace process is manipulated in response to the water content of process air.

BACKGROUND

This application is a division of application Ser. No. 211,984, filedDec. 1, 1980, now U.S. Pat. No. 4,351,818.

The invention relates to process control. In another aspect, theinvention relates to a furnace. In a further aspect, the inventionrelates to an energy efficient carbon black reactor and its use.

In certain types of furnaces, temperature control is extremelyimportant, as excessive temperatures can damage the furnace. Where thefurnace is employed to carry out a process, such as the production ofcarbon black, the temperature within the furnace is desirably maintainedwithin a relatively narrow range, so as to produce attractive quantitiesof a desirable product.

A problem which has long existed in the art is that of accuratelymeasuring the temperature within the furnace for control purposes.Conventional temperature sensors cannot long withstand the extremelyelevated temperatures encountered in a furnace, typically in excess of2000° F. Reliable temperature control in a furnace, especially where thecharacteristics of the air and fuel which are combusted in the furnaceare subject to fluctuation, has proved a difficult problem. Fuelcharacteristics which can vary from time to time include its temperatureand composition. Air characteristics which can vary significantly fromtime to time include its temperature, pressure, and relative humidity.

Especially in processes for the production of carbon black, waste heatwhich was not utilized in the pyrolysis reaction escapes the furnace inthe gaseous effluent. It would be extremely desirable to capture andrecycle as much of this waste heat as possible thereby reducing theamount of fuel required to maintain the desired furnace temperature. Dueto the high temperatures involved, it would be further desirable tocontrol recycle of heat without undertaking a direct measurement ofmaximum furnace temperature.

OBJECTS OF THE INVENTION

It is an object of this invention to provide an apparatus for recyclingwaste heat back into a furnace, thereby conserving fuel.

It is another object of this invention to provide a process forrecycling waste heat back into a furnace, thereby conserving fuel.

SUMMARY OF THE INVENTION

According to one embodiment of the invention, a furnace employingindirect heat transfer between its outgoing effluent and incomingcombustion supporting air and a quench of its outgoing effluent prior toindirect heat exchange with the incoming air is provided with a meansfor regulating its flow of quench at least partially in response to thewater content of the incoming air. In a prior art apparatus employing ameans for regulating the flow of quench in response to the temperatureof the quenched effluent, it was found, surprisingly, that furnacetemperature frequently declined as ambient temperature increased. Thisanomaly was traced to the containment in the air stream of greateramounts of water vapor at higher temperatures. To compensate for thefall in furnace temperature, the fuel rate in the prior art apparatuswas increased. By utilizing the apparatus of the present invention, thedrop in furnace temperature caused by a rising dew point can beanticipated, and the rate of quench flow reduced before furnacetemperature drops significantly. The combustion supporting air is thuspreheated to a higher temperature in times of rising humidity than inthe prior art apparatus, and waste heat is more efficiently utilized tomaintain furnace temperature than in the prior art apparatus, whichutilized a greater flow of fuel in times of rising humidity to maintaindesired furnace temperature.

According to another embodiment of the invention, the rate of quenchfluid flow to a furnace is controlled in response to a signal which isderived at least in part from the relative humidity of the air suppliedto the furnace.

BRIEF DESCRIPTION OF THE DRAWINGS

The FIGURE is a schematic illustrating certain features of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the FIGURE, a furnace 2 is provided with a conduit 4 forthe introduction of combustible material and a conduit 6 for theintroduction of combustion-supporting gas. Preferably, the conduit 4communicates with a gaseous hydrocarbon fuel supply, such as naturalgas, and the conduit 6 communicates with a source of freeoxygen-containing gas, such as air. Preferably, air is caused to flowthrough the conduit 6 by a blower 7 associated therewith. The fuel fromconduit 4 and air from conduit 6 are admixed and combusted in thefurnace 2 to form a heated mass of combustion gases which flows as astream from a zone 8 of the furnace 2 and through an effluent conduit10.

In a preferred embodiment, the furnace 2 is a carbon black reactor. Aconduit 12 for the introduction of a carbonaceous feedstock communicateswith the zone 8. Feed introduced into the furnace via the conduit 12contacts the hot combustion gases and decomposes to form carbon black.In this case, the effluent conduit 10 carries particulate carbon blacksuspended in the combustion gases.

It is desirable during the manufacture of carbon black that the fuelintroduced into the furnace 2 via the line 4 be essentially completelycombusted prior to the point in the combustion gas stream where thecarbonaceous feedstock is introduced by the line 12. This is commonlyachieved by combusting the fuel and air in combustion tunnels (notshown) oriented tangentially to the zone 8, as is well known by thoseskilled in the art, (see, for example, U.S. Pat. No. 2,564,700) althoughthe present invention is not limited to carbon black reactors employingtangential combustion tunnels.

It is also desirable to cool the effluent stream in conduit 10 to amanageable temperature during the production of carbon black. To thisend, a quench fluid, for example, water or cool gases are introducedinto the conduit 10 via a conduit 14 which communicates with the conduit10 to cool the effluent stream. The effluent in the conduit 10 is cooledfrom a temperature of 2400° or more to a temperature of 2000° F. orless, generally to a quenched effluent temperature of between about 800°F. and about 1800° F., to avoid heat induced damage to the materialsfrom which the conduit 10 is formed, for example, cast refractory, ordamage to other downstream equipment.

According to one aspect of the present invention, the air in line 6 ispreheated before introduction into the furnace 2 by indirect contact inheat exchange relationship with the effluent flowing through the conduit10. Preferably, the air is preheated in a heat exchanger 26 which isassociated with the conduit 10 downstream of introduction of quenchfluid from the conduit 14. Usually, because of ease of fabrication andlow maintenance requirements, the heat exchanger 26 comprises a jacketin communication with the line 6 and surrounding a portion of theexterior of the conduit 10. Thus, at least a portion of the air line 6is in heat exchange relationship with a portion of the effluent conduit10. A suitable spiral partition can be positioned in the jacket, ifdesired, to cause a spiral flow of the air around the exterior of theconduit 10 and in countercurrent relationship with the flow of effluentthrough the conduit 10, to cause good indirect heat transfer between theincoming air and the outgoing effluent. See, for example, U.S. Pat. No.3,369,870. Other types of heat exchangers can be employed if desired,but generally at some sacrifice in pressure drop through the conduit 10.

A valve 28 positioned in the line 6 allows control of the rate of airflow through the conduit 6. Preferably, a motor valve is deployed in theline 6 upstream of the heat exchanger 26 to effect flow control. A flowcontroller 30 is operably associated with the motor valve 28 andcompares a set point signal 32 representative of the desired flowthrough the conduit 6 with a signal 34 which is representative of theactual flow through the conduit 6. The valve 28 is manipulated inresponse to a signal 33 from the flow controller 30 which is establishedin response to the comparison of the actual and desired flow signals,for example, so as to decrease the difference between the signals 32 and34. The signal 34 is established by a means 36 associated with theconduit 6 for establishing a signal representative of the flow of airthrough the conduit 6, such as a flow transducer. In this manner, theair flow rate through the conduit 6 can be adequately controlled.

In similar fashion, the flow rate of carbonaceous feedstock, whenemployed, is controlled by a valve 38, such as a motor valve, disposedwithin the line 12. The valve 38 is manipulated by a flow controller 40which compares a set point signal 42 representative of a desired flowrate of carbonaceous feedstock with a signal 44 representative of therate of flow in the conduit 12. The signal 44 is established by a flowtransducer 46 associated with the conduit 12. The flow controller 40establishes a signal 43 and the valve 40 is manipulated in response tothe signal 43 to control the rate of flow in the conduit 12, such as bybeing manipulated so as to decrease the difference between the signals42 and 44.

In accordance with another aspect of the present invention, the rate offuel flow in the conduit 4 is controlled by a valve 48 disposed withinthe conduit 4. The valve 48 is manipulated in response to a signal 50from a flow controller 52. The signal 50 can be mechanical, electrical,hydraulic or pneumatic in nature, for example. The flow controller 52receives a set point signal 54 representative of a desired flow rate inthe conduit 4, preferably from a computer 56, and a flow rate signal 58which is representative of the flow rate of fuel in the conduit 4, froma means 60 associated with the conduit 4 for establishing a signalrepresentative of the flow rate of fuel in the conduit 4, such as a flowtransducer. The signal 50 is established by the flow controller 52 inresponse to the signals 54 and 58. The valve 48 is manipulated inresponse to the signal 50 to control the rate of flow through theconduit 4, such as by being manipulated so as to decrease the differencebetween the signals 54 and 58.

The fuel rate set point signal 54 (FGAS) is preferably established bythe computer 56 in response to a relationship between:

(a) the enthalpies of the components (I) of the fuel gas stream 4 at thefuel gas temperature (TGAS);

(b) the relative composition of the fuel gas stream, such as the molepercent (X) of each component (I) in the fuel gas stream 4;

(c) the heat of combustion (NBTU) of the fuel gas stream 4 per standardunit of volume;

(d) the enthalpies of the components (I) of the preheated air stream 6at the preheated air stream temperature (TAIR);

(e) the enthalpies of the components (I) of the combustion gas stream 10at the desired combustion gas temperature (TZA);

(f) the moisture content of air entering the conduit 6, such as the molefraction of water vapor (XHA) in the preheated air stream 6 expressed asthe ratio moles water vapor/moles dry air; and

(g) the standardized total flow rate (FAIR) of air flowing through theconduit 6.

For example, a preferred relationship for establishing the signal 54 inunits of thousands of standard cubic feet per hour from the aboveparameters can be expressed as:

    FGAS=FAIR*[XHA*ENTH(TZA,9)+(0.79+X.sub.N2) *ENTH(TZA,14)+0.21*ENTH(TZA,13)-ENTH(TAIR,8)-XHA*ENTH(TAIR,9)]/[379*NBTU+X.sub.N2 *ENTH(TGAS,1)+X.sub.CH4 *ENTH(TGAS,3)+X.sub.C2 *ENTH(TGAS,4)+X.sub.C3 *ENTH(TGAS,5)+X.sub.C4 *ENTH(TGAS,6)+(X.sub.H +X.sub.C6 +X.sub.C5)*ENTH(TGAS,7)-(7*X.sub.H +6*X.sub.C6 +5*X.sub.C5 +4*X.sub.C4 +3*X.sub.C3 +2*X.sub.C2 +X.sub.CH4)*ENTH(TZA,10)-(8*X.sub.H +7*X.sub.C6 +6*X.sub.C5 +5*X.sub.C4 +4*X.sub.C3 +3*X.sub.C2 +2*X.sub.CH4)*ENTH(TZA, 9)+(11*X.sub.H +9.5*X.sub.C6 +8*X.sub.C5 +6.5*X.sub.C4 +5*X.sub.C3 +3.5*X.sub.C2 +2*X.sub.CH4)*ENTH(TZA,13)].

This and other relationships set forth in this specification arepreferably solved by a digital computer adapted to periodically solvethe relationship from sensed inputs, such as once about every 6 seconds.

In the above equation, the term ENTH(T,I) is representative of theenthalpy of component I at temperature T. The (T,I) terms utilized inthis specification are defined as follows:

                  TABLE I                                                         ______________________________________                                        Fuel Temp, T = TGAS                                                           Preheated Air Temp, T = TAIR                                                  Ambient Air Temp, T = TAMB                                                    Desired Flame Temp, T = TZA                                                   Desired Quenched Smoke Temp, T = TSMO                                         Quench Water Temp, T = TH20                                                   N.sub.2, I = 1                                                                CO.sub.2, I = 2                                                               CH.sub.4, I = 3                                                               C.sub.2, I = 4                                                                C.sub.3, I = 5                                                                C.sub.4, I = 6                                                                C.sub.5, I = 7                                                                Air, I = 8                                                                    H.sub.2 O, I = 9                                                              CO.sub.2, I = 10                                                              CO, I = 11                                                                    C.sub.2 H.sub.2, I = 12                                                       O.sub.2, I = 13                                                               N.sub.2, I = 14                                                               CH.sub.4, I = 15                                                              H.sub.2, I = 16                                                               Oil, I = 17                                                                   ______________________________________                                    

The term X_(I) in the FGAS equation is representative of the molepercent X of component I in the fuel stream 4, where I is defined asfollows:

                  TABLE II                                                        ______________________________________                                        Component                 I                                                   ______________________________________                                        methane                   CH.sub.4                                            acetylene, ethylene, ethane                                                                             C.sub.2                                             propyne, propene, propane C.sub.3                                             butyne, butenes, butane   C.sub.4                                             pentyne, pentenes, pentane                                                                              C.sub.5                                             hexyne, hexenes, benzene, hexane                                                                        C.sub.6                                             heavies                   C.sub.H                                             ______________________________________                                    

At least one signal 62 representative of ENTH(TGAS,1), ENTH(TGAS,3),ENTH(TGAS,4), ENTH(TGAS,5), ENTH(TGAS,6) and ENTH(TGAS,7) is establishedby a means 64 for establishing signals representative of the enthalpiesof the components in the fuel gas stream 4. The at least one signal 62is received by the computer 56. Preferably, the means 64 is a computeror subassembly capable of solving the relationships

    ENTH(TGAS,1)=(6.94)(TGAS)+(0.00010115)(TGAS).sup.2 -416.76

    ENTH(TGAS,3)=(8.25)(TGAS)+(0.0024166)(TGAS).sup.2 -504

    ENTH(TGAS,4)=(11.699)(TGAS)+(0.0068702)(TGAS).sup.2 -726.68

    ENTH(TGAS,5)=(16.865)(TGAS)-(0.0062446)(TGAS).sup.2 +(0.000093069)(TGAS).sup.3 -1009.6

    ENTH(TGAS,6)=(21.01)(TGAS)+(0.15488)(TGAS).sup.2 -1316.3

    ENTH(TGAS,7)=(26.077)(TGAS)+(0.01934)(TGAS).sup.2 -1634

where enthalpy is in BTU/mole and TGAS is in °F. The at least one signal62 is established by the means 64 in response to a signal 66 establishedby a means 68 associated with the conduit 4 for establishing a signalrepresentative of the temperature of the fuel gas stream, such as atemperature transducer. The signal 66 is received by the means 64.

At least one signal 70 representative of X_(N2), X_(CH4), X_(C2),X_(C3), X_(C4), X_(C5), X_(C6) and X_(H) is established by a means 72associated with the conduit 4 for establishing signals representative ofthe relative composition of the fuel gas stream 4. The at least onesignal 70 is received by the computer 56. A suitable means 72 is achromatographic analyzer.

A signal 74 representative of the net heating value per unit volume,NBTU, of the fuel gas stream 4 is established by a suitable means 76 forestablishing a signal representative of the heating value of the fuelgas flowing in conduit 4. The signal 74 is received by the computer 56.The heating value of the fuel gas can be expressed in terms of energyunits per standard unit of volume, BTU per standard cubic foot, forexample, which the fuel gas will produce when completely combusted. Themeans 76 receives at least signal 70 for deriving the value of the fuelgas stream from the chromatographic analyzer 72 and establishes thesignal 74 in response thereto. One technique for deriving such a valuefrom a chromatographic analysis is disclosed by R. L. Kindred et al inU.S. Pat. No. 3,095,728.

At least one signal 78 representative of ENTH(TAIR,8) and ENTH(TAIR,9)is established by a suitable means 80 for establishing signalsrepresentative of the enthalpies of the components in the preheated airstream 6. The at least one signal 78 is received by the computer 56.Preferably, the means 80 comprises a computer or subassembly capable ofsolving the relationships:

    ENTH(TAIR,8)=(6.9065)(TAIR)+(0.000082564)(TAIR).sup.2 +(0.00000018764)(TAIR).sup.3 -414.73

    ENTH(TAIR,9)=(7.93163)(TAIR)+(0.000711015)(TAIR).sup.2 -414.95

where enthalpy is in BTU/mole and TAIR is in °F. For solution of theabove relationships, the means 80 receives a signal 82 representative ofthe temperature of the preheated air in the conduit 6 and establishesthe at least one signal 78 in response thereto. The signal 82 isestablished by a means 84 associated with the conduit 6 for establishinga signal representative of the temperature of the preheated air in theconduit 6, such as a temperature transducer.

At least one signal 86 representative of ENTH(TZA,9), ENTH(TZA,14),ENTH(TZA,13) and ENTH(TZA,10) is established by a suitable means 88 forestablishing signals representative of the enthalpies of the componentsin the combustion gases formed in the zone 8. The at least one signal 86is received by the computer 56. Preferably, the means 88 comprises acomputer or subassembly capable of solving the relationships

    ENTH(TZA,9)=(7.93163)(TZA)+(0.000711015)(TZA).sup.2 -414.95

    ENTH(TZA,10)=(11.0865)(TZA)+(0.00063853)(TZA).sup.2 +(0.0000000046844)(TZA).sup.3 -1611.1

    ENTH(TZA,13)=(5.8643)(TZA)+(0.002007)(TZA.sup.2)-(0.00000051072)(TZA).sup.3 -269.49

    ENTH(TZA,14)=(5.8945)(TZA)+0.00098873(TZA).sup.2 -(0.00000013018)(TZA).sup.3 -10.43

where enthalpy is in BTU/mole and TZA is in °F. The at least one signal86 is established by the means 88 in response to a set point signal 9Owhich is representative of a desired flame temperature in the furnace 2.The signal 90 is received by the means 88.

A signal 92 representative of XHA is established by a suitable means 94for establishing a signal representative of the moisture content of airentering conduit 6. The signal 92 is received by the computer 56.Preferably, the means 94 comprises a computer or subassembly capable ofsolving the relationship:

    XHA=[10**(5.319480+(-0.00058601588*TDEW)+(-2119.6319/(301.00159+TDEW))]/[PATM-(10**(5.319480+(-0.00058601588*TDEW)+(-2119.6319/(301.00159+TDEW))]

where XHA is representative of the ratio moles water/moles dry air, TDEWis the dew point temperature in °F. of air entering the conduit 6 andPATM is the atmospheric pressure in inches of mercury at which the dewpoint was obtained. The signal 92 is established by the means 94 inresponse to a signal 96 and preferably a signal 100. The means 94receives the signal 96, which is established by a suitable means 98 forestablishing a signal representative of the dew point of process airentering the conduit 6, such as a dew point transducer. The signal 96 isrepresentative of TDEW. The signal 100 is representative of the pressureof air entering the conduit 6 and established by a suitable means 102for establishing a signal representative of the pressure of process airentering the conduit 6, such as a pressure transducer. The signal 100 isreceived by the means 94. The signal 100 is representative of PATM.

A signal 1O4 representative of FAIR is established by a suitable means106 for establishing a signal representative of the standardized flowrate of air through the conduit 6. The signal 104 is received by thecomputer 56. Devices suitable for performing the function of means 106are well known by those having ordinary skill in the art. The signal 104is established by the means 106 in response to a signal 108, a signal112 and a signal 116. Preferably, the signal 104 is representative ofFAIR in units of 1000 standard cubic feet per hour. The signals 108, 112and 116 are received by the means 106. The means 106 receives the signal108 which is representative of fluid flow rate through the conduit 6from a means 110 associated with the conduit 6 for establishing a signalrepresentative of fluid flow, such as a flow transducer. The signal 112,which is representative of the fluid pressure in the conduit 6 isestablished by a means 114 associated with the conduit 6 forestablishing a signal representative of the fluid pressure in theconduit 6, such as a pressure transducer. The signal 116, which isrepresentative of the temperature of fluid in the conduit 6 isestablished by a means 118 associated with the conduit 6 forestablishing a signal representative of the temperature in the conduit6, such as a temperature transducer.

In accordance with another aspect of the present invention, the rate ofquench fluid flow in the conduit 14 is controlled in response to asignal which is derived at least in part from the moisture content ofair entering the conduit 6. The apparatus 2 is thus provided with ameans 119 associated with the quench fluid conduit 14 for controllingthe quench fluid flow rate through the conduit 14 in response to amodified quench fluid flow rate set point signal 126 derived at least inpart from the moisture content of air entering the conduit 6 and asignal 128 representative of the rate of fluid flow through the quenchfluid conduit 14. Preferably, the means 119 comprises a flow controller124 which receives the signals 126 and 128 and establishes a signal 122in response to the signals 126 and 128 which is received by a valve 120,such as a motor valve, associated with the conduit 14. The valve 120 ismanipulated in response to the signal 122 to control the rate of fluidflow through the conduit 14. The signal 122 can be electrical,hydraulic, mechanical, or pneumatic in nature, for example, and isderived at least in part from the moisture content of the air enteringthe conduit 6. The signal 128 is established by a means 130 associatedwith the conduit 14 for establishing a signal representative of the flowrate of quench fluid in the conduit 14, such as a flow transducer. Thesignal 126, which is representative of the desired flow rate of quenchfluid, is derived at least in part from the moisture content of the airentering the conduit 6 by a means 131 for establishing a modified quenchfluid flow rate set point signal derived at least in part from themoisture content of air entering the air conduit. Preferably, the means131 comprises a means 133 for establishing a quench fluid flow ratemodifying signal 134(WFH20) derived at least in part from the moisturecontent of air entering the conduit 6, and a means 135 for establishinga quench fluid flow rate set point signal 178 derived at least in partfrom the temperature of the quenched effluent flowing through theconduit 10. The modified signal 126 is established in response to arelationship between the set point signal 178 and the modifying signal134.

Preferably, the quench fluid flow rate modifying signal is establishedin response to a relationship between:

(a) the temperature of the quench fluid flowing through the conduit 14(TH20);

(b) the air flow rate through the conduit 6 (FAIR);

(c) the moisture content of air entering the conduit 6 (XHA);

(d) the moisture content of air entering the conduit 6 at a previoustime (XHAR);

(e) the enthalpy of water vapor near the intake of the conduit 6(ENTH(TAMB,9)); and

(f) the enthalpy of water vapor in the quenched effluent stream inconduit 10 (ENTH(TMS0,9) and (ENTH2(TMS0,9)).

Preferably, the relationship between the above parameters is establishedby a computer 132 which establishes the signal 134. For example, asuitable relationship for establishing the signal 134 in response to theabove parameters can be expressed as:

    ΔFH20=[FAIR*(1000/379)*(XHA-XHAR)*(ENTH(TSMO,9)-ENHTH(TAMB,9))*18.015]/(ENTH2(TSMO,9)+19658-18.015*TH20)

where ΔFH20 is representative of the signal 134.

A signal 138 representative of TH20 is established by a means 140associated with the conduit 14 for establishing a signal representativeof the temperature of the fluid flowing through the conduit 14, such asa temperature transducer. The signal 138 is received by the computer132.

A signal 142 representative of FAIR is established by the means 106 orits equivalent for establishing a signal representative of fluid flowthrough the conduit 6. The signal 142 is received by the computer 132.

A signal 144 representative of XHA is established by the means 94 or itsequivalent for establishing a signal representative of the water contentof the air entering the conduit 6. The signal 144 is received by thecomputer 132.

A signal 146 representative of XHAR is established by a means 148 forestablishing a signal representative of the water content of the airentering the conduit 6 at a previous point in time. As shown, the means148 is a delay switch as well known by those having ordinary skill inthe art which receives a signal 150 representative of XHA from the means94 or its equivalent for establishing a signal representative of themole ratio water vapor/dry air of the air entering the conduit 6, and,after a suitable delay period, which can range from milliseconds tominutes, for example, six seconds, transmits the previously received XHAsignal as XHAR to the computer 132.

A signal 152 representative of ENTH(TAMB,9) is established by a means154 for establishing a signal representative of the enthalpy of watervapor in air entering the conduit 6. Preferably, means 154 is a computeror subassembly capable of solving the relationship.

    ENTH(TAMB,9)=(7.93163)(TAMB)+(0.000711015)(TAMB).sup.2 -414.95

where TAMB is ambient temperature in °F. and ENTH(TAMB,9) is measured inBTU/mole. The relationship is solved by the means 154 in response to asignal 156 representative of TAMB which is established by a means 158for establishing a signal representative of the ambient temperatureadjacent the intake to the conduit 6 such as a temperature transducer.The signal 156 is received by the means 154.

Signals 160 and 162 representative of ENTH(TSM0,9) and ENTH2I(TSM0,9)are established by means 164 and 166, respectively, for establishing asignal representative of the desired enthalpy of water vapor in thequenched effluent flowing through the conduit 10 and entering intoindirect heat exchange relationship with the air in the air conduit 6.The signals 160 and 162 are received by the computer 132. Preferably,the means 164 is a computer or subassembly capable of solving therelationship

    ENTH(TSMO,9)=(7.93163)(TSMO)+(0.000711015)(TSMO).sup.2 -414.95

and the means 166 is a computer or subassembly capable of solving therelationship

    ENTH2(TSM0,9)=(7.93163)(TSMO)+(0.000711015)(TSMO).sup.2

where ENTH is in BTU/mole and TSMO is in °F.

The signals 160 and 162 are established by the means 164 and 166 inresponse to at least one set point signal 168 representative of TSMO.TMSO is representative of a temperature which is determined by themetallurgical limit of equipment downstream of the conduit 10. Usually,TSMO is representative of a temperature of 1500° F. or less.

A signal 172 representative of the temperature of the quenched effluentin the conduit 10 is established by a means 170 associated with theconduit 10, such as a temperature transducer. The signal 172 is receivedby a temperature controller 174. The temperature controller establishesa signal 178 in response to the signal 172 and a set point signal 176which is representative of the desired temperature of the effluent inthe conduit 10 to provide the signal 178 which is representative of adesired flow rate of quench fluid through the conduit 14 derived atleast in part from the temperature of the quenched effluent flowingthrough the conduit. The signal 176 is representative of a temperatureof less than the temperature at which equipment damage would occur, forexample, a temperature of 1400° F.

The signals 134 and 178 are received by a means 180 for modifying theset point signal 178 with the modifying signal 134 according to apredetermined relationship. The means 180 can be a summing junction,well known to those having ordinary skill in the art. The means 180establishes the signal 126 which is received as the modified set pointsignal by the flow controller 124.

While the invention has been described in detail for purposes ofexplanation and illustration, it is not intended to be limited thereby.Rather, reasonable modifications and additions which would be apparentto one with ordinary skill in the art are included within the scope ofthis invention.

What is claimed is:
 1. In a carbon black reactor comprisinga meansdefining a first reaction zone; a fuel conduit communicating with saidfirst reaction zone; an air conduit communicating with said firstreaction zone; an effluent conduit communicating with said firstreaction zone; a means for heat exchanging the effluent in said effluentconduit with the air in said air conduit to pre-heat the air prior tointroduction into said first reaction zone; and a means for defining aquench fluid conduit communicating with said effluent conduit betweensaid first reaction zone and said means for heat exchanging; theimprovement comprising:(a) a means for determining the moisture contentof the air and for establishing a first signal representative of themoisture content of the air, and means for generating a modified quenchfluid flow rate signal derived at least in part from the moisturecontent of air entering the air conduit; (b) a means for determining theflow rate of the quench fluid and generating a representative signal;and (c) a flow control means in association with the quench fluidconduit for controlling the quench fluid flow rate through the quenchfluid conduit in response to the modified quench fluid flow rate signaland the signal representative of the rate of fluid flow through thequench fluid conduit.
 2. A carbon black reactor as in claim 1 whereinthe means for establishing the modified quench fluid flow rate signalcomprises:(a) a means for determining the temperature of the effluententering into a heat exchange relationship with the air in the airconduit and generating a representative effluent temperature signal, and(b) a means for establishing a quench fluid flow rate set point signalderived at least in part from said effluent temperature signal; (c) ameans for modifying the quench fluid flow rate set point signal inresponse to the quench fluid flow rate modifying signal and establishingthe modified quench fluid flow rate set point signal.
 3. A carbon blackreactor as in claim 2 wherein said means for establishing said firstsignal also establishes a second signal representative of a previousmoisture content of the air entering said air conduit and wherein themeans for establishing the quench fluid flow rate modifying signalcomprises:(a) a means for determining the standardized flow rate of airthrough the air conduit and establishing a third signal representativeof the standardized flow rate of air through the air conduit; (b) ameans for determining the enthalpy of the water vapor in the airentering the air conduit and establishing a fourth signal representativeof the enthalpy of water vapor entering the air conduit; (c) a means fordetermining the enthalpy of the water vapor in the effluent conduitentering into an indirect heat exchange relationship with the air in theair conduit and establishing a fifth signal and a sixth signalrepresentative of the enthalpy of water vapor in the effluent conduitentering into indirect heat exchange relationship with the air in theair conduit at a desired effluent temperature; (d) a means fordetermining the temperature of the fluid flowing through the quenchfluid conduit and establishing a seventh signal representative of thetemperature of the fluid flowing through the quench fluid conduit; and(e) a means for receiving the first signal, the second signal, the thirdsignal, the fourth signal, the fifth signal, the sixth signal and aseventh signal and establishing the quench fluid flow rate modifyingsignal in response to a predetermined relationship between said first,second, third, fourth, fifth, sixth and seventh signals.
 4. A carbonblack reactor as in claim 3 wherein the predetermined relationshipbetween said first, second, third, fourth, fifth, sixth and seventhsignals is given by

    (FAIR*1000/379*(XHA-XHAR)*((ENTH(TSMO,9)-ENTH(TAMB,9))*18.015)/(ENTH2(TSMO,9)+19658-18.015*TH20);

wherein FAIR is the third signal, wherein XHA is the first signal,wherein XHAR is the second signal, wherein ENTH(TSMO,9) is the fifthsignal, wherein ENTH(TAMB,9) is the fourth signal, wherein ENTH2(TSMO,9)is the sixth signal, and wherein TH20 is the seventh signal.
 5. A carbonblack reactor as in claim 4 wherein the means for establishing thequench fluid flow rate set point signal comprises a temperaturetransducer associated with the effluent conduit for establishing asignal representative of the temperature in the effluent conduit and atemperature controller for receiving the signal established by thetemperature transducer, comparing it to a signal representative of adesired temperature in the effluent conduit, and establishing the quenchfluid flow rate set point signal in response to the comparison.
 6. Acarbon black reactor as in claim 5 wherein the means for controlling thequench fluid flow rate through the quench fluid conduit comprises a flowtransducer associated with the quench fluid conduit for establishing thesignal representative of the rate of quench fluid flow through thequench fluid conduit, a valve in the quench fluid conduit, and a flowcontroller in manipulative association with the valve which receives thesignal from the flow transducer, compares it with the modified quenchfluid flow rate signal, and manipulates the valve in response to thecomparison.